*{
    margin :0;
    padding: 0;
}
.body {
    display:flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background-image: url('https://i.alipayobjects.com/e/201311/1V4o5xqtgr_src.jpg');
    overflow:hidden;
    background-size:cover;
}
.box{
   width: 240px;
   height: 200px;
   padding: 20px;
   border: 1px solid #ccc;
   background-color: #473e3eb8;
   position: absolute;
   top: 20%;
   left: 50%;
   margin:20px;
}
.head{
    font-size:20px;
    text-align: center;
    color: #ffffffd4;
    margin-bottom: 20px;
}
.input-box{
    width: 100%;
    height: 20px;
    font-size: 15px;
    margin: 10px;
}
.btn-box{
    text-align:right;
}
.wen-box{
    text-align: center;
    font-size: 15px;
}
#bit{
    width:200px;
    height:40px;
    background-color: rgb(127, 146, 255);
}